Conventional optical storage media, such as CD, DVD, require a lens to focus the light source on a recording layer of the storage media to read and write data. The size of the recording spot is restricted by the optical diffractive property. To improve the recording density of the optical storage media, it is necessary to address the optical diffractive issues.
The optical pickup is the most important component in the optical storage device. The operation of an optical pickup includes projecting a laser beam to the surface of the media, and using an object lens to guide the reflected laser beam to an optical sensor for reading and writing. Because the media quality of different manufactures and the stability of a loading tray may vary, a playing device may be very selective and critical to the media quality and result in the discrimination of certain media.
An approach to solving the above problem is to allow a fine tuning of the object lens so that the laser beam can be precisely guided to the right angle for the optical pickup to perform the reading and writing correctly. The conventional approach is to connect the object lens to an actuator, which can provide the movement forces in both focusing direction and tracking direction for tuning the laser beam direction.
However, the conventional actuator fails to meet the demands of the reactive speed and the precision in the current application; therefore, it is important to develop an actuator to provide fast and precise movement forces to tune the lens.